For Trollope, a book’s success ultimately depended upon ‘perfect delineation of character’ rather than plot. Yet he thought that the plot for Orley Farm ‘was probably the best I had ever made’ — a judgement with which his public agreed.

Nonetheless, his own opinion diverged from theirs in one significant respect: he thought that in depicting his chief character Lady Mason, he had failed, but, as so often, his own assessment of his work was faulty. In fact, Orley Farm is technically an astonishing achievement. Quite soon after his tale starts, we learn that twenty years earlier Lady Mason had been accused — and acquitted — of forging her husband’s will. A display of unwise high-handedness by her spoiled son Lucius angers a tenant of the Orley Farm estate unnecessarily, and triggers off a fresh investigation.

Gradually, the reader is brought to suspect that Lady Mason might, after all, have been guilty: that she might just possibly have forged the codicil which bequeathed Orley Farm to her son: and she may be in growing danger of being put on trial again not just for forgery but for perjury as well. At this point, before half his tale has run, Trollope displays great narrative skill, and supreme confidence, by revealing the truth. From this point we are dealing not with a ‘whodunnit?’ story, but with a ‘Will-she-get-away-with-it?’ – and the answer to that question is in doubt till the end.

Uninterested in the melodramatic possibilities of the plot, Trollope concentrates instead on the harrowing effects of long-concealed guilt on a weak but not worthless character, who committed a great crime for simple love of her son, and in the end could not escape her punishment.

Orley Farm teems with other life and lives of all kinds: the tragic portrait of Sir Peregrine Orme – too sheltered a gentleman to believe in the unworthy motives of the woman he befriended, and the marvellously evocative picture of a real Victorian Christmas at Noningsby, the home of Judge Staveley, are chief among the incidental delights in this fine novel.

Trollope also considered that publication was helped by the inclusion of numerous illustrations by Sir John Millais. The author suggested his childhood home — Julians in Harrow — as a model for his fictional farm, and was enchanted by the results. ‘I know no book graced with more exquisite pictures’.